Recently, there exists a radio tag reading apparatus which reads information from a radio tag attached to a commodity, in a store such as a clothing store, using RFID (Radio Frequency Identification) technology, for example. This radio tag reading apparatus reads commodity information and so on from a radio tag attached to a commodity. For the reason, a store reads commodity information from radio tags attached to commodities displayed on a shelf or the like and commodities housed in a box, using the radio tag reading apparatus, to perform management of a stock status of the commodities in the store. In addition, the radio tag reading apparatus is also widespread in business worlds other than clothes.
An operator of a store trains a handy type radio tag reading apparatus on a radio tag attached to a commodity such as clothes displayed on a shelf, and radiates a radio wave for information reading from the radio tag reading apparatus, and receives a response radio wave from the radio tag, to receive information from the radio tag. And, when radiating the radio wave toward the radio tag, the radio tag reading apparatus performs carrier sense so as to avoid interference with a radio wave which is being radiated from another radio tag reading apparatus, and thereby executes radiation of the radio wave using an unused channel.
Incidentally, it takes a definite time for a radio tag reading apparatus to read information of a radio tag. For the reason, when the number of the radio tags to be read is large, it takes a great deal of time for reading information of all the radio tags.